The Malaria Genomic Unit uses the malaria parasite genome databases and develops new resources to study the mechanism of drug resistance, gene regulation during parasite sexual development, and parasite population diversity and evolution. Building on progress made last year, we have now collected additional single nucleotide polymrphisms (SNPs) from genes on chromosome 1, 2, 4, 5, 6, 13 and 14 of Plasmodium falciparum. To study chromosomal haplotypes, population structures, and recombination rate variation, we have also genotyped 183 SNPs on chromosome 3 from 99 worldwide isolates. This data set is being analyzed for publication. We found that recombination rate vary greatly among parasite populations and across chromosome 3. We have also finished sequencing the mitochondrial genome from 176 P. vivax isolates and 5 other primate malaria species. Our data support the hypothesis of host switches and origin of P. vivax from Asian monkeys. Another major effort of our laboratory is to study gene expression and regulation associated with the parasite sexual differentiation. We have identified a gene that may play a key role in gametocyte development using microarray and genetic mapping. Phenotypic changes are being evaluated after genetic knockout of the target gene. We are currently evaluating the function of the gene. Monoclonal antibodies against gametocyte were produced, and the target proteins recognized by the antibodies are being identified. The potential of the antibodies in blocking transmission are also being tested.